Drawing More Power Than You Think

Energy efficient building design has come a long way to improve building system energy performance. But what happens when the users move in? Additional equipment and appliances added after occupancy can dramatically impact actual building performance with surprising and expensive results.

Rendered View of The Packard Foundation's New Home in Los Altos, California (Image courtesy EHDD Architecture)

Plug loads and process loads have been long considered outside the design team’s scope yet they can account for more than 1/3 of a building’s overall energy use. Net Zero Energy design, however, requires that all loads in a building be reduced. No client wants to increase the capacity of their costly solar PV array to cover energy usage generated by inefficient office equipment.

A rendering of the Exploratorium’s future new home at Pier 15 located between the Embarcadero and the San Francisco Bay. This Embarcadero view looks at the Exploratorium’s new main entrance facade with the new Observatory Building at the other end along the Bay waterfront and the East Bay beyond. (Image courtesy EHDD Architecture)

EHDD Architecture has completed four Net Zero buildings and currently has two in construction. In each of these projects, plug loads have proven to be a significant design consideration. As such, EHDD has conducted plug load studies of different projects to better determine the sources of these hidden loads and to develop strategies to reduce them. The studies uncovered some surprising truths about plug loads:

  • The new home for San Francisco’s Exploratorium is aiming to be Net Zero Energy. Luckily for the design team, the existing exhibitions and office spaces provided an excellent opportunity to better understand the organization’s use of plug loads. The study found that a wealth of equipment, exhibits, and lighting were being left on all night, accounting for 37% of the facility’s plug load energy use. Through user education, plug load monitoring, better scheduling, and automatic timers, most of these loads will be drastically reduced or even eliminated.
  • The Packard Foundation also had existing facilities that could be monitored during the design development phase of their new Net Zero Energy office building. The biggest surprise was the water coolers, which were found to account for 13% of plug load energy use. The study found that through a combination of purchasing policies, scheduling, and improved equipment efficiency, plug loads could be reduced by 58%, saving $820,000 on the cost of the PV system.  For example, by purchasing the MOST efficient monitors instead of just settling for Energy Star rated monitors, they were able to reduce annual energy use for each monitor by 59% from 134 kWh to 56kWh.
  • The Net Zero Energy office building for Integrated Design Engineers and Associates found that the server and computers accounted for a whopping 88% of the facility’s plug loads. The project contains extensive monitoring that will give detailed data on plug loads and overall energy performance and help guide plug load reduction strategies.
  • Scott Shell, a Principal at EHDD Architecture, also conducted an extensive plug load study of his Net Zero Electrical home in Marin. He found that one of his biggest energy hogs was from equipment and appliances left on standby mode. These ‘phantom’ loads accounted for 26% of his plug loads, the worst being a built-in stereo system that had come with the house. He was able to eliminate most of these loads with power strips and thereby saving money on his solar PV system.


ASHRAE/NetZERO Conference with Scott Shell & Peter Rumsey (Video courtesy EHDD Architecture)

The plug load studies have revealed some easy to implement energy saving tips that we now suggest to every client:

  1. Establish a purchasing policy that specifies the best performing Energy Star and EPEAT certified equipment.
  2. Consider replacing older equipment and appliances with newer, more efficient versions. Energy Star and other resources have calculators to determine the financial benefits of an upgrade.
  3. Switch out all incandescent light bulbs to compact fluorescent lamps.
  4. Install occupancy sensor controlled plug load strips in each office/workstation and educate staff on proper use.
  5. Install automatic timers on things such as vending machines, copiers, coffee makers, water coolers etc. to turn off unused equipment after hours.
  6. Put all copiers and printers on standby modes.
  7. Use PC Power Management software over the local network such as those offered by Verdiem, Faronics Technologies, or Big Fix Inc. to power down computers when they are not in use.
  8. Use plug load meters to measure actual energy use of equipment and appliances. You may be surprised by what you discover!
IDeAs Z2 Design Facility/Office in San Jose, California: South Elevation with Sliding Glass Doors and Solar PV Shades. (Photo by David Wakely and photo courtesy Integrated Design Engineers and Associates)
IDeA Z2 Design Facility Office in San Jose, California Office Interior: Elements such as fluorescent light fixtures, energy efficient computer monitors, and occupancy sensor controlled plug load strips contribute to the reduction of plug loads. (Photo by David Wakely and photo courtesy Integrated Design Engineers and Associates)

Resources:

  1. www.energystar.gov (for efficient appliances and equipment).  You can SORT the list of energy star products in the Excel format to find the MOST efficient appliance in each category.
  2. http://www.toptenusa.org/ (a shorter list of the top 10 efficient Energy Star products in different categories)
  3. Efficientproducts.org (electronics)
  4. www.80plus.org (computers, servers etc)
  5. www.wattstopper.com (power strips, controls, occupancy sensors etc)
  6. www.verdiem.com (PC Power Management
  7. www.epeat.net (environmental rating of electronics)
  8. www.greenpeace.org/international/campaigns/toxics/electronics/how-the-companies-line-up (Greenpeace Guide to Greener Electronics)
  9. www.p3international.com/products/special/P4400/P4400-CE.html (Kill-A-Watt plug load meter)
About Janika McFeely 0 Articles
Janika McFeely, Guest Contributor, is a LEED® AP BD+C, a designer at EHDD Architecture, and has an extensive research background in sustainable design issues in addition to her architectural qualifications. While completing her Masters of Architecture, she assisted in the development of the Canadian Green Building Council’s LEED® Canada Version 1.0 Reference Guide, as well as other research efforts related to sustainable architecture. Since joining EHDD Architecture in 2007, she has directed the LEED certification process for all office projects which include a wide range of building typologies–from exhibit-related and educational facilities to civic and commercial environments. She is currently part of the team working on the design and construction of a new net zero energy headquarters for the Packard Foundation in Los Altos, California.

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